It is known to, for the purpose of reinforcement, cooling assistance or the like, cover a board provided with a heat generating component such as a surface mount device and an electronic component with a structural component such as a covering member and a cover.
For example, Patent Document 1 describes an electronic component which has a wiring board, a surface mount device mounted on the wiring board, and a covering member covering the surface mount device. According to Patent Document 1, the covering member has a ceiling part formed by a ceramic member like a flat plate, and a leg part formed by a columnar member having a height at least as high as the surface mount device. Moreover, according to Patent Document 1, the surface mount device and the leg part of the covering member are mounted on the board with solder.
Further, as a similar technique, for example, Patent Document 2 describes a wiring board which has an element and a shied cap joined so as to cover at least part of an element mounting part. According to Patent Document 2, for example, solder mounting of the element and solder bonding of the shield cap are done simultaneously in one solder reflow.
Further, a related technique is described in Patent Document 3, for example. Patent Document 3 describes an electronic circuit unit soldered with the leg part of a metal cover inserted in a through hole provided on a board. According to Patent Document 3, a solder land is provided at the corner of the board, and a reinforcing land is provided on the lower surface of the board. At least one of the solder land and the reinforcing land has a cut-out part for removing air.
Further, a related technique is described in Patent Document 4, for example. Patent Document 4 describes an electronic circuit unit which has an insulating board with an electronic component mounted and a metal cover for covering the electronic component. According to Patent Document 4, the insulating board is provided with a cover attachment hole formed through the insulating board and having an electrode on the inner wall. Moreover, the cover includes a cover terminal extending to the end edge and located in the cover attachment hole and fixed with solder. The cover terminal has, at the tip end side, a grip part for holding the solder filled between the front-end side and the end edge.
Patent Document 1: WO2006/059556
Patent Document 2: Japanese Unexamined Patent Application Publication No. JP-A 2001-015976
Patent Document 3: Japanese Unexamined Patent Application Publication No. JP-A 2011-192668
Patent Document 4: Japanese Unexamined Patent Application Publication No. JP-A 2008-112921
The structural components as described in Patent Documents 1 to 4 may have a role as a cooling aid that dissipates heat generated from a heat generating component through a board (an insulating board, a wiring board). However, according to the techniques described in Patent Documents 1 to 4, the structural component is in contact with the board only at a leg part provided at the corner of the structural component. For this reason, a place where heat is transferred from the board to the structural component is limited, which results in a problem that increase of heat dissipation performance is difficult.
Thus, there has been a problem that increase of heat dissipation performance of a structural component mounted on a board is difficult.